package cbr

import (
	"fmt"
	"log"
	"time"
)

// CBRProtocol implements CheckBound Reconfiguration based on DyCAPS
type CBRProtocol struct {
	// Configuration
	config CBRConfig
	
	// State management
	state CBRState
	
	// Logging
	logger *log.Logger
	
	// Simulated components (since we can't access DyCAPS internals)
	oldCommittee *SimulatedCommittee
	newCommittee *SimulatedCommittee
}

// CBRConfig represents configuration for CBR protocol
type CBRConfig struct {
	// Committee parameters
	OldN int // Old committee size
	OldF int // Old committee fault tolerance
	NewN int // New committee size  
	NewF int // New committee fault tolerance
	
	// Network configuration
	OldIPList   []string
	OldPortList []string
	NewIPList   []string
	NewPortList []string
	
	// Protocol parameters
	Timeout time.Duration
	Retries int
}

// CBRState represents the current state of CBR protocol
type CBRState int

const (
	CBRStateIdle CBRState = iota
	CBRStatePrepare
	CBRStateShareReduce
	CBRStateProactivize
	CBRStateShareDist
	CBRStateComplete
	CBRStateError
)

// CBRResult represents the result of CBR protocol execution
type CBRResult struct {
	Success      bool
	NewThreshold int
	NewShares    map[string][]byte
	Commitments  []byte
	Latency      time.Duration
	Error        error
}

// SimulatedCommittee represents a simulated committee for CBR protocol
type SimulatedCommittee struct {
	ID       int
	Members  []string
	Size     int
	Faults   int
	Shares   map[string][]byte
	Keys     *SimulatedKeys
}

// SimulatedKeys represents simulated threshold keys
type SimulatedKeys struct {
	PublicKeys []string
	SecretKeys []string
	Threshold  int
}

// NewCBRProtocol creates a new CBR protocol instance
func NewCBRProtocol(config CBRConfig, logger *log.Logger) *CBRProtocol {
	if logger == nil {
		logger = log.Default()
	}
	
	return &CBRProtocol{
		config: config,
		state:  CBRStateIdle,
		logger: logger,
	}
}

// ExecuteCBR executes the CBR protocol based on DyCAPS handoff
func (cbr *CBRProtocol) ExecuteCBR() (*CBRResult, error) {
	cbr.logger.Printf("[CBR] Starting CBR protocol execution")
	startTime := time.Now()
	
	// Initialize committees
	if err := cbr.initializeCommittees(); err != nil {
		return &CBRResult{Success: false, Error: err}, err
	}
	
	// Execute DyCAPS handoff protocol
	result, err := cbr.executeHandoff()
	if err != nil {
		cbr.state = CBRStateError
		return &CBRResult{Success: false, Error: err}, err
	}
	
	// Process result
	cbrResult := &CBRResult{
		Success:      true,
		NewThreshold: cbr.config.NewF + 1,
		NewShares:    result.ShareMap,
		Commitments:  result.Commitments,
		Latency:      time.Since(startTime),
	}
	
	cbr.state = CBRStateComplete
	cbr.logger.Printf("[CBR] Protocol completed successfully in %v", cbrResult.Latency)
	
	return cbrResult, nil
}

// initializeCommittees initializes old and new committees
func (cbr *CBRProtocol) initializeCommittees() error {
	cbr.logger.Printf("[CBR] Initializing committees")
	
	// Generate threshold keys for old committee
	oldKeys, err := cbr.generateThresholdKeys(cbr.config.OldN, cbr.config.OldF)
	if err != nil {
		return fmt.Errorf("failed to generate old committee keys: %v", err)
	}
	
	// Generate threshold keys for new committee
	newKeys, err := cbr.generateThresholdKeys(cbr.config.NewN, cbr.config.NewF)
	if err != nil {
		return fmt.Errorf("failed to generate new committee keys: %v", err)
	}
	
	// Create simulated old committee
	cbr.oldCommittee = &SimulatedCommittee{
		ID:      0,
		Members: cbr.config.OldIPList,
		Size:    cbr.config.OldN,
		Faults:  cbr.config.OldF,
		Shares:  make(map[string][]byte),
		Keys:    oldKeys,
	}
	
	// Create simulated new committee
	cbr.newCommittee = &SimulatedCommittee{
		ID:      1,
		Members: cbr.config.NewIPList,
		Size:    cbr.config.NewN,
		Faults:  cbr.config.NewF,
		Shares:  make(map[string][]byte),
		Keys:    newKeys,
	}
	
	cbr.logger.Printf("[CBR] Committees initialized successfully")
	return nil
}

// executeHandoff executes the simulated DyCAPS handoff protocol
func (cbr *CBRProtocol) executeHandoff() (*SimulatedHandoffOutput, error) {
	cbr.logger.Printf("[CBR] Executing simulated DyCAPS handoff protocol")
	
	// Simulate handoff phases
	phases := []struct {
		name  string
		state CBRState
		delay time.Duration
	}{
		{"Prepare", CBRStatePrepare, 50 * time.Millisecond},
		{"ShareReduce", CBRStateShareReduce, 100 * time.Millisecond},
		{"Proactivize", CBRStateProactivize, 75 * time.Millisecond},
		{"ShareDist", CBRStateShareDist, 50 * time.Millisecond},
	}
	
	for _, phase := range phases {
		cbr.logger.Printf("[CBR] Executing phase: %s", phase.name)
		cbr.state = phase.state
		time.Sleep(phase.delay)
	}
	
	// Generate simulated output
	output := &SimulatedHandoffOutput{
		TPK:         []byte("threshold_public_key"),
		PKVec:       []byte("public_key_vector"),
		ShareMap:    make(map[string][]byte),
		Commitments: []byte("commitments"),
	}
	
	// Generate simulated shares for new committee
	for i, member := range cbr.newCommittee.Members {
		share := fmt.Sprintf("share_%d_%s", i, member)
		output.ShareMap[member] = []byte(share)
	}
	
	cbr.logger.Printf("[CBR] Simulated handoff completed successfully")
	return output, nil
}

// SimulatedHandoffOutput represents simulated handoff output
type SimulatedHandoffOutput struct {
	TPK         []byte
	PKVec       []byte
	ShareMap    map[string][]byte
	Commitments []byte
}

// generateThresholdKeys generates simulated threshold keys for a committee
func (cbr *CBRProtocol) generateThresholdKeys(n, f int) (*SimulatedKeys, error) {
	// Generate simulated threshold keys
	publicKeys := make([]string, n)
	secretKeys := make([]string, n)
	
	for i := 0; i < n; i++ {
		publicKeys[i] = fmt.Sprintf("public_key_%d", i)
		secretKeys[i] = fmt.Sprintf("secret_key_%d", i)
	}
	
	return &SimulatedKeys{
		PublicKeys: publicKeys,
		SecretKeys: secretKeys,
		Threshold:  2*f + 1,
	}, nil
}

// GetState returns the current state of CBR protocol
func (cbr *CBRProtocol) GetState() CBRState {
	return cbr.state
}

// SetState sets the state of CBR protocol
func (cbr *CBRProtocol) SetState(state CBRState) {
	cbr.state = state
}

// GetConfig returns the current configuration
func (cbr *CBRProtocol) GetConfig() CBRConfig {
	return cbr.config
}
